This invention relates to pupillometry, and more particularly, to a system which includes means for inducing a reaction in the iris and pupil of an eye and observing such reaction.
Observation of the size of the pupil of an eye, determined by the state of the iris thereof under generally steady-illumination conditions, and also the reaction of the iris and pupil upon application of light thereto, can provide valuable information for determining the physical state of the person involved. For example, if the person is being anesthetized in preparation for, for example, an operation, the observation of the reflex of the iris upon application of light thereto can be extremely valuable in determining the extent to which the anesthetic is affecting the patient. That is, if there is little or no reaction of the iris to a relatively sudden application of light, the patient can be assumed to be further anesthetized than if such reaction is relatively great or brisk.
Additionally, measurement of the absolute size of the pupil of the eye may provide valuable information. For example, it is well known that the pupils of a person who is under the effect of certain drugs, such as morphine, are reduced in size. With certain other drugs, the pupils may be enlarged. Thus, the observation of size of the pupil and the reaction of the iris and pupil to a relatively sudden application of light, can provide very valuable information toward determining the physical state of the person involved.
Systems which are generally related to the problem involved above are disclosed in U.S. Pat. No. 2,303,221 to Moy, U.S. Pat. No. 2,573,464 to Lowenstein et al, U.S. Pat. No. 3,533,683 to Stark et al, U.S. Pat. No. 3,533,684 to Stark et al, and U.S. Pat. No. 3,535,026 to Coss. It is to be noted that, while such systems have been found relatively effective in the uses for which they were designed, certain of these systems are relatively complicated in construction (U.S. Pat. Nos. 2,573,464, 3,533,683 and 3,533,684). Furthermore, the devices of U.S. Pat. Nos. 2,303,221 and 3,535,026 include means which allow the measurement of the size of the pupil, but provide no means for properly allowing observation of the reaction or reflex of the iris and pupil of the eye to application of light thereto.
Other known devices used along these lines are a template defining a plurality of holes, one of which is lined up with the pupil for measuring the size thereof, a ruler with which the pupil is measured, and a photographing system which takes a photo of the eye, from which photograph the pupil size can be measured.
Of general interest in this area are U.S. Pat. No. 1,918,540 to Hartinger, and U.S. Pat. No. 3,012,462 to Kosche et al.